Every year the Washington State Department of Transportation (WSDOT) conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of average annual daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2011, WSDOT calculated that between 980 and 21,000 vehicles per day used the highway, mostly in the Yakima area.[16]

^Washington State Legislature (March 17, 1937), "Chapter 207: Classification of Public Highways", Session Laws of the State of Washington, Session Laws of the State of Washington (1937 ed.), Olympia, Washington: Washington State Legislature, pp. 1008–1009, retrieved January 13, 2013, (a) Secondary State Highway No. 11A; beginning at Connell on Primary State Highway No. 11, thence in a westerly direction by the most feasible route to Yakima on Primary State Highway No. 3; the director of highways of the State of Washington shall provide suitable facilities for vehicle and pedestrian crossing of the Columbia river at the point where Secondary State Highway No. 11A, as herein described, crosses the river, and shall maintain said means of crossing at the expense of the State of Washington and without charge to the traveling public.